1. Field of the Invention
This invention related to an electromagnetic induction type processing apparatus, and more particularly to an electromagnetic induction type processing apparatus which uses electromotive force generated by a magnetic field supplied from the outside as a power supply to operate a functional device disposed in the apparatus and containing conductive substance.
2. Description of the Related Art
An apparatus is in the past available wherein a magnetic field is interlinked with a coil to generate electromotive force in the coil and the generated electromotive force is utilized as power in the apparatus.
An example of an existing processing apparatus of the type described is shown in FIG. 1.
Referring to FIG. 1, the power supplying apparatus 1 is used to supply power to a processing apparatus 2 and includes a power supply 11 and a coil 12 for generating, for example, a sine wave signal. In the power supplying apparatus 1, the power supply 11 generates and supplies a sine wave signal to the coil 12 so that a magnetic field (linkage magnetic field 21 indicated by lines of magnetic force of broken line arrow marks) is radiated from the coil 12 to an external space.
The processing apparatus 2 utilizes power acquired from the power supplying apparatus 1 to perform processes and includes a coil 31, a regulator 32 and a circuit 33. The processing apparatus 2 is, for example, carried by a user and moved toward the power supplying apparatus 1 by the user until it is positioned closely to the power supplying apparatus 1. Thereupon, the circuit field radiated from the power supplying apparatus 1 is interlinked with the coil 31 to generate electromotive force in the coil 31. The electromotive force generated in the coil 31 is converted into a fixed voltage by the regulator 32 and then supplied to the circuit 33. The circuit 33 operates with the electromotive force to implement a predetermined function which the processing apparatus 2 has.
In the apparatus described above, in order to sufficiently assure a linkage circuit field, an obstacle which may disturb the circuit field does not exist around the coils 12 and 31, and the power supply 11 in the power supplying apparatus 1 and the regulator 32 and the circuit 33 in the processing apparatus 2 are formed from electronic circuits which handle an electric signal. Therefore, the power supplying apparatus 1 and the processing apparatus 2 contain some conductive substance. If such conductive substance exists in the region of the linkage magnetic field, then eddy current is generated. The eddy current generates a secondary magnetic field in a direction opposite to that of the linkage magnetic field. As a result, the efficiency in power supply is deteriorated.
Therefore, in the existing apparatus, in order to positively assure the space for the linkage magnetic field for power supply, the conductive substance of the electronic circuits and so forth is disposed in a spaced relationship away from the linkage magnetic field as seen in FIG. 1.
FIG. 2 shows another existing processing apparatus. The processing apparatus is adopted popularly in IC cards and so forth.
Referring to FIG. 2, the processing apparatus (IC card) 40 shown includes a coil 41, a regulator 42 and a circuit 43. The coil 41 is disposed so as to extend along an outer periphery of the processing apparatus 40. Therefore, the regulator 42 and the circuit 43 are disposed within the coil 41. However, if the regulator 42 and the circuit 43 have a comparatively great size with respect to the area of the coil 41, then they make an obstacle to the linkage magnetic field 21 and deteriorates the efficiency in power transmission from the power supplying apparatus 1 to the processing apparatus 40. Therefore, usually the area of the regulator 42 and the circuit 43 is reduced sufficiently with respect to the area of the coil 41 thereby to reduce the influence on the power transmission.
FIG. 3 shows a further existing processing apparatus.
Referring to FIG. 3, the processing apparatus (IC card) 50 shown includes a coil 51, a regulator 52 and a circuit 53. A magnetic member 54 is disposed within the coil 51 of the processing apparatus 50 as seen in FIG. 3. The circuit member 54 may be formed, for example, using ferrite as a main raw material. Since the magnetic substance has a property of collecting magnetic fluxes, where the configuration of the processing apparatus 50 described above is employed, eddy current which may be generated by a conductive substance of the circuit 53, regulator 52 and so forth disposed in contact with the surface of the magnetic member 54 can bed prevented (a processing apparatus of the type described is disclosed, for example, in Japanese Patent Laid-Open No. 2005-234827). It is to be noted, however, that the incorporation of the magnetic substance in this instance makes restrictions to the size and the volume and raises the cost.